package homework;

import java.util.Scanner;

public class ExistedChar {
    public static void main(String[] args) {
        String res = new String("");
        Scanner scanner = new Scanner(System.in);
        while(scanner.hasNext()){
            int i = 0;
            String s = scanner.nextLine();
            while (i < s.length()){
                char c = s.charAt(i);
                char[] tmp = res.toCharArray();
                for (int j = 0; j < tmp.length; j++) {
                    if(tmp[j] == c){
                        break;
                    }
                    if(j == tmp.length - 1&&tmp[j] != c){
                        res += c;
                    }
                }
                i++;
            }
            System.out.println(res);
        }
    }
}
